The prior art teaches various methods and machines for forming pinch bottom and flat bottom bags and for forming bundles of the bags.
U.S. Pat. No. 9,663,320 relates to a method for forming packs of flat bags, a continuous line of bags moving in an oriented direction of advance. The bags are moved onto a receiving table on which the bags are stacked while being stopped from moving in the oriented direction of advance by an abutment. The continuous line of bags is converted into a line of overlapped bags before stacking the latter, and the bags are separated on the receiving table by a separating means comprising a separating device. During this operation, a separating device is inserted by a movement in the separating direction perpendicular to the plane of the bags between a preceding bag and a following bag in the overlapped line in such a way that, when the following bag stops against the abutment, it is supported at least partially by the separating means.
US patent publication 20150141228 relates to a machine for manufacturing flat bottom bags. The machine includes a drum for carrying at least one blank having a flattened tubular shape in an advancing direction, a scoring apparatus upstream of the drum for marking on the blank a folding line which is transverse with respect to the advancing direction, a front gripper on the drum that grips a front edge of the blank on the drum and carries the blank, and a first lateral gripping means on the drum that grips the lateral edges of the blank in the region of the first folding line.
US patent publication 20090110534 relates to a bag supply apparatus for supplying bags onto a conveyor for transporting a bag bundle. The bag bundle is stacked such that an upper level bag is shifted forward. The apparatus includes a bag lifting device, which is provided with a pair of bag support members disposed facing one another on the left and right sides near the rear edge of a belt conveyor. The apparatus further includes a rotation mechanism, which imparts translational motion of rotation in symmetric in a vertical plane with respect to the conveyance direction of the belt conveyor. The bag supporting portions of the bag support members contact the bag bundle from below to lift up the rear edge portion of the bag bundle and then separate from the bag bundle outwardly. While the bag supporting portions lift the bag bundle, a new bag is fed into the space between the conveyance surface of the belt conveyor and the bag bundle.